Washing appliance with temperature indicating means

ABSTRACT

The present invention comprises means in an automatic washing machine for sensing internal washing liquid temperature, registering a reading of such temperature, and holding the registered reading after completion of the operational cycle whereby the operator of the machine can determine, when washed items are later removed from the machine, if faulty washing performance may have been due to insufficient heat in the washing liquid.

finite States Guth June 4, 1974 [54] WASHING APPLIANCE WITH 2,605,736 8/1952 Cook et al 116/129 B TEMPERATURE INDICATING MEANS 3,254,533 6/1966 Tongret ..L 73/362 AR 3,513,796 7/1970 Bebinger 134/57 D X [75] Inventor: Lauren W. Guth, Louisville, Ky.

[73] Assign G l El t i C Primary ExaminerRichard C. Queisser Louisville, Assistant Examiner-Frederick Shoon Filed: Dec. 1972 Attorney, Agent, or FirmFrancis H. Boos, Jr.

[21] Appl. No.: 318,389 [57] ABSTRACT The present invention comprises means in an auto- [52] 11.8. CI. 73/343 R, 73/3639, 116/129 B, matic washing machine for sensing internal washing 134/57 1), 134/113 1 liquid temperature, registering a reading of such tem- [51] int. 0...... Gfllk 13/02, GOlk 5/64, B08d 3/00 perature, and holding the registered reading after [58] Field of Search 73/343 R, 343.5, 363.9; completion of the operational cycle whereby the oper- 116/129 A, 129 B; 134/57 D, 113' ator of the machine can determine, when washed items are later removed from the machine, if faulty [56] R f nc Cit d washing performance may have been due to insuffi- UNITED STATES PATENTS 1/1952 Jansen 73/3639 x cient heat in the washing liquid.

9 Claims, 5 Drawing Figures WASHING APPLIANCE WITH TEMPERATURE INDICATING ANS I BACKGROUND OF THE INVENTION An automatic dishwashing machine cannot provide optimum cleaning efficiency even though the machine is functioning quite properly if the water conducted into its wash chamber is cold or only luke warm. Ideally, the incoming water should be at a temperature of 140 or higher during the major portion of the operational cycle. Initially, when the machine is first placed into operation, some liquid carry-over from the previous operation may be present in the pump. This liquid carry-over combines with relatively cool water coming from the household conduit portion between the machine and the remotely located hot water storage tank. Once the first pre-rinse period is completed, the relatively cool water will'have been pumped from the machine and all incoming water thereafter should be hot water conducted directly from the hot water storage tank. If the temperature of hot water in the household storage tank is below 140 F. due to a low temperature setting of the storage tank heater or because a large quantity of hot water has been used just previous to placing the dishwashing machine into operation, the temperature of water utilized in the various rinse and wash periods of the machines operational cycle will be too low to provide optimum cleaning efficiency. This cannot only result in soil remaining on the dishes at the end of the operational cycle but can also result in such soil being baked onto the dishes during the final drying period of the cycle. The housewife, upon discovering the soiled condition of the dishes after operation of the machine, will normally be unaware of the reason and will be inclined to blame the machine. This can result in unnecessary and expensive service calls wherein a service man is requested to diagnose a problem in the function of a perfectly operating machine.

The aforedescribed situation is prevented by utilization of the present invention wherein means is provided in a dishwashing machine to automatically inform the housewife if the temperature of water used in the machine during the operational cycle was below the manufacturers recommendation. The present invention comprehends a means of indicating to the housewife or other operator of a dishwashing machine whether or not the temperature of the water during the already completed operational cycle of the machine was adequate to provide the cleaning efficiency of which the machine is capable. Where the apparatus indicates that the water temperature was too low, the housewife can react by adjusting the heater of her hot water storage tank to provide hotter water or she can adjust her schedule in accordance with family needs whereby operation of the dishwashing machine will not follow a high usage of hot water for other purposes.

SUMMARY OF THE INVENTION the machines operator. Release of the locking means thereafter occurs as a function of the next operational cycle of the machine.

' BRIEF DESCRIPTION OF THE DRAWING I FIG. 1 is a fragmentary side elevational view of an automatic dishwashing machine having a side wall thereof cut away to reveal some of the machines internal components; I I

FIG. 2 is a fragmentary side elevational view of the door of the dishwashing machine first shown in FIG. 1,

shown in a somewhat larger scale as compared to FIG. 1 and having a portion thereof cut away to enable illustration of structure pertinent to the preferred embodi- DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing and particularly to FIG. 1 thereof, there is illustrated an automatic dishwasher 10 having an outer cabinet 12 defining therein a washing enclosure or wash chamber 14. Disposed within the wash chamber 14 are lower and upper racks l6 and 18 which are adapted to receive and support dishes or other articles to be washed within the wash chamber 14. A door 20 is provided in one wall of the cabinet 12, pivotal about a hinge means 22, to provide access to the wash chamber 14. When the door 20 is pivoted downwardly, the upper rack 18 can be at least partially withdrawn from the upper portion of the wash chamber 14 by means of a slide and roller system provided therefor. Similarly, the lower rack 16 can be at least partially withdrawn from the lower portion of thewash chamber 14 by means of roller supports that track over the inside surface of the open door 20.

The wash chamber 14 has a bottom wall 24 which gradually slopes to a low point near the center of the dishwasher. projecting upwardly from the bottom wall 24 near the center of the wash chamber 14 is a tubular pedestal 26 which rotatably supports a spray arm 28. The spray arm 28 has a plurality of orifices 30 through which liquid is ejected to accomplish washing action upon articles supported in the racks l6 and 18. At least one of the orifices 30 is directed such that the reactive force created by liquid being ejected therefrom causes rotation of the spray arm 28.

Liquid is -circulated through the pedestal 26 and then through the spray arm 28 by a motor-pump unit comprising a pump 32 which is driven by a reversible electric motor 34. The pump and motor are secured together as a unit which is suitably supported from the bottom wall 24 of the wash chamber 14. The pump 32 has an annular sump inlet or intake 36 for receiving collected liquid from the bottom of the wash chamber 14 whereby it can be pumped and recirculated through the spray arm 28. The pump 26 is designed such that reversing the motor 34 causes liquid received through the annular intake 36 to be pumped outwardly through a drain hose 38 to the household sewage system. With this arrangement, water, or washing liquid composed of water and detergent added thereto, entering the pump through its intake 36 will be pumped either into the spray arm 28 and thence to the wash chamber 14 or will be discharged from the dishwashing machine through the drain hose 38. v

A sequence control means or timer control 40 (shown schematically in FIG. 5 is utilized as the means of automatically controlling the operational cycle of the dishwashing machine it). The timer control 40 is adapted to energize and de-energize various operating components of the dishwasher at predetermined times in the operational cycle whereby washing, rinsing and drying operations are performed on the dishes stored in the wash chamber M.-The control system for the dishwashing machine comprises the timer control 30 which includes a synchronous electric timer motor 42 that drives a plurality of rotatable cams 44, 46, 48, 50 and 52. A control knob 54 is accessible at the front side of the machine MD for manipulation by the operator whereby the cycle of the machine can be initiated, adjusted or interrupted. The knob 54, the timer motor 42 and the cams 44-52 are housed in the timer control 40 and are mechanically interconnected in a well-known manner. I

With reference to FIG. 5, power is available to the control system of the machine 10 through terminals L, and L A safety switch 56 is operativewith the closing of the door such that the control system cannot be energized until the door 10 is securely closed. The control knob 54 is rotatably manually advanced a short distance by the machine operator whereby cam'44 rotates to close a switch 58. The switch 58 controls the energization of the timer motor 412 which, when energized, drives all of the cams 44-52. Once the timer motor 42 is energized it drives all the cams in unison, and each of the cams 46-52 are designed to actuate and close or open a switch associated therewith whereby various components in the machine are energized and deenergized at predetermined times in the cycle. For example, a heating element 60 is in series with a switch 62, and a solenoid 64 controlling a water valve 56 is in series with a switch 68..

The motor 34 includes a main winding 70 and a pair of start windings 72 and 74. When winding 78 and winding 72 are energized at the same time, the motor 34 rotates in a direction appropriate to cause operation of the spray arm 28. When windings 70 and 74 are energized-at the same time the motor 34 starts to rotate in the direction effective to cause draining ofliquid out through drain conduit 38. In the conventional manner, a start relay 76 may be provided in series with the winding 70, in controlling relationship to a switch 78 and in series with both windings 72 and 74. A relatively high current level, such as that which flows through the relay 76 when the motor is not yet rotating, causes relay 76 to close switch 78. As the motor comes up to speed, the level of energization drops substantially; as a result, relay 76 lets switch 78 move to its normally open position to assure de-energization of whichever of windings 72 and 74 was previously energized during startup. Thus, the motor 34 may be caused to start in either direction of rotation, and then it will continue to run on the winding 70 alone after it comes up to speed.

The direction of rotation of the motor 34 is determined by a switch 80 which is movable into engagement with either of two contacts to provide for selection of start windings 72 or 74 respectively. Both the start windings, through s'witch 80, and the main winding are connected through a switch 82 so that the entire motor energizing circuit is connected across lines L and L and is controlled by the switch 82.

The conventional configuration and arrangement of the cams 44-52 is usually such that a complete operational cycle of the dishwashing machine 10 involves, in order: one or' more pre-rinse periods; a wash period; and one or more post-rinse periods. The last post-rinse period, or final rinse, is normally followed by a drying period wherein the articles are heated by the electrical heating element 60 to facilitate their drying within the wash chamber 14. Each of the conventional pre-rinse wash and rinse operations include, in order: a fill period wherein the pump motor 34 remains de-energized and the water inlet valve 66 is open to admit liquid to the wash chamber 14, a rinse or wash period wherein the inlet valve 66 is closed and the motor 34 is energized to take liquid from the wash chamber 14 and recirculate it through the spray arm 28, and a drain period wherein the inlet valve 66 is closed and the motor 34 is reversibly energized to direct liquidfrom the wash chamber 14 outwardly through the drain conduit 38 to the household sewage system.

. In accordance with the present invention, the dishwashing machine 10 shown in FIG. 1 includes apparatus housed within the door 20 for sensing the temperature of water within the wash chamber 14 at a point in the operational cycle when the hottest water available during the cycle is being used. As shown in FIG. 2, the door 20 includes an outer appearance panel 84 and an inner wash chamber wall panel 86 which define therebetween a hollow area 88. Mounted within the area 88 is a temperature responsive assembly 90 including a thermally responsive means in the form of a coil 92 mounted on a heat conducting shaft 94. The shaft 94 is mounted to the panel 86 and has a heat sensor element 96 disposed to be subjected to the environmental conditions within the wash chamber 14. As shown in FIG. 4, the coil 92 is mounted with its inner end 98 in fixed heat conducting relationship to the shaft 94 and its outer end 100 is adapted to be free to move in an arcuate pathway as the coil 92 expands or contracts in re sponse to temperature change.

As shown in FIG. 2, a plate 102 is pivotally mounted to a bracket 104 and projects vertically downwardly past the assembly 90. At the lower end of the plate 102 a small resilient hollow bellows 106 is disposed between the lower end of the plate 102 and the panel 86. A biasing means in the form of a small spring 108 is provided to normally bias the lower end of the plate 102 toward the panel 86 except when pressure increases within the "bellows 106 whereby it expands to pivot the plate 102 toward the outer appearance panel 84. The bellows 106 is in liquid flow communication with the drain conduit 38 (see FIG. 1) by means of a communicating hose 110 such that the bellows is caused to expand whenever pressure is increased within the hose 110 during drain flow through the drain conduit 38.

FIG. 2 also shows that plate 102 is provided with an opening 112 therethrough at a position opposite the outer end 100 of the coil 92; The end 100 of the coil 92 is provided with two portions projecting laterally therefrom; an indicator or pointer member 114 and a smallrigid stop rod 116. The pointer 114 projects through the opening M2 whereby it is visible through a window opening H8 in the appearance panel 84. The stop rod 116 has its projecting end resting against the surface of the plate T102 adjacent the opening H2.

The stop rod 116 normally rests in contact with the plate 102 whereby the end l of the coil 92 is prevented from moving in response to changes in temperature effecting the coil 92, however, when the pump 26 is pumping liquid from the wash chamber l4 outwardly through the drain conduit 38 the increased pressure in the hose 110 causes the bellows 106 to expand and slightly pivot the plate M2 to release thestop rod 116 such that the end 100 of the coil 92 is freed to move. By this arrangement, the pointer lll l projecting from the end 100 of the coil 92 will adjust to give a new reading on a simple scale such as shown in H6. 3 on the front side of the door 20 only when the motor 26 is operating to pump liquid out of the chamber B4. The plate 102 thus serves as a locking means to normally prevent response of the indicator 114, and the bellows 106 acts as a means of releasing the indicator at the desired time.

The reading indicated to the machine operator, after completion of the operational cycle of the machine, will be the temperature of water utilized in the last rinse period of the cycle. The operator is therefore not required to examine the machine or the temperature indicator heretofore described at any specific time during the operation of the machine but may check the position of the pointer at any time after completion of the operational cycle if soil is discovered remaining on the dishes when they are removed from the machine. Even though the door and the interior of the wash chamber 14 gets substantially hotter during the drying period at the end of the cycle, the apparatus heretofore described will not record this hotter temperature since the pointer will be held in the position attained at the last pump drainout by means of the stop rod 116 being in contact with the plate 102 to prevent movement of the pointer thereafter.

lt is recognized that the apparatus of the present invention may be modified to give the desired function of indicating if the water was hot enough for optimum cleaning efficiency during the operation of the dishwashing machine without having the assembly merely adapted to react in response to pressure change in the liquid drain conduit 38. For example, the bellowsl06 and the hose ll0 could be eliminated and a bimetal element could be substituted for the plate 102. Such an element could be disposed generally in the orientation shown for the plate H02 whereby it would be contacted by the stop rod 1T6 to normally prevent movement of the pointer 114. The bimetal plate or element could then be wired in parallel with the motor 34 whereby it would be energized whenever the motor 34 was energized in the direction to cause pump-out ofliquid from the machine. Such a bimetal element 120 is schematically illustrated in parallel with motor 34 in FIG. to

represent an alternative embodiment of this invention. Still another alternative means of modifying the apparatus shown and described would be to utilize a solenoid (not shown) to control pivotal movement of the plate 102 shown in FIG. 2 whereby energization of the solenoid would pivot the plate away from the stop rod l re to release the pointer 1 14$ for movement. The solenoid could be in the circuit in parallel with the motor 34 whereby it would be energized when the motor was energized. Either of the two alternative modifications heretofore described would function to prevent movement of the indicator 114 during the drying period at the end of the operational cycle of the dishwashing machine.

! claim:

l. A washing appliance of the type utilizing liquid contact for cleaning including a plurality of operative components adapted for operation in a predetermined sequence to perform an operational cycle and automatic control means therewith for conducting the appliance through the operational cycle,

thermally responsive sensing means for sensingtem perature change of the washing liquid in the machine during the operational cycle,

indicator means operatively associated with the sensing means to respond to reactan ce of the sensing means to temperature change, releasable locking means serving to normally prevent response of the indicator means to temperatures other than that of the washing liquid, and

means for releasing the locking means adapted to be actuated to release as an incident of the operation of one of the operative components of the appliance. I

2. The combination of claim ll wherein one of the operative components of the appliance is a pump for circulating washing liquid and the releasing means releases as an incident of operation of the pump.

3. The combination of claim 1 wherein one of the operative components is a motor-pump unit for circulating washing liquid, and the releasable means releases as an incident of energizing the motor-pump unit.

' 4. The combination of claim l wherein the indicator means has a portion thereof visible to the machine operator.

5. The combination of claim l wherein the operational cycle of the machine includes a washing period preceding a drying period at the end of the cycle, and the locking means is adapted to prevent response of the indicator means after completion of the washing period whereby the indicator means is prevented from responding by the locking means until the next operational cycle of the appliance.

6. The combination of claim 1 wherein one of the operative components is a pump for circulating washing liquid and draining washing liquid from the appliance and the releasing means is adapted to respond to the pump pressure to release the indicator means.

7. The combination of claim 1 wherein the releasing means includes a flexible bellows.

8. The combination of claim l wherein the releasing means is adapted to be electrically energized to release the locking means.

9. The combination of claim 1 wherein the operational cycle includes sequential washing and rinsing periods followed by a final draining period, and the releasing means is adapted to be released during the final 

1. A washing appliance of the type utilizing liquid contact for cleaning including a plurality of operative components adapted for operation in a predetermined sequence to perform an operational cycle and automatic control means therewith for conducting the appliance through the operational cycle, thermally responsive sensing means for sensing temperature change of the washing liquid in the machine during the operational cycle, indicator means operatively associated with the sensing means to respond to reactance of the sensing means to temperature change, releasable locking means serving to normally prevent response of the indicator means to temperatures other than that of the washing liquid, and means for releasing the locking means adapted to be actuated to release as an incident of the operation of one of the operative components of the appliance.
 2. The combination of claim 1 wherein one of the operative components of the appliance is a pump for circulating washing liquid and the releasing means releases as an incident of operation of the pump.
 3. The combination of claim 1 wherein one of the operative components is a motor-pump unit for circulating washing liquid, and the releasable means releases as an incident of energizing the motor-pump unit.
 4. The combination of claim 1 wherein the indicator means has a portion thereof visible to the machine operator.
 5. The combination of claim 1 wherein the operational cycle of the machine includes a washing period preceding a drying period at the end of the cycle, and the locking means is adapted to prevent response of the indicator means after completion of the washing periOd whereby the indicator means is prevented from responding by the locking means until the next operational cycle of the appliance.
 6. The combination of claim 1 wherein one of the operative components is a pump for circulating washing liquid and draining washing liquid from the appliance and the releasing means is adapted to respond to the pump pressure to release the indicator means.
 7. The combination of claim 1 wherein the releasing means includes a flexible bellows.
 8. The combination of claim 1 wherein the releasing means is adapted to be electrically energized to release the locking means.
 9. The combination of claim 1 wherein the operational cycle includes sequential washing and rinsing periods followed by a final draining period, and the releasing means is adapted to be released during the final draining period. 